Voltage-nonlinear resistors

ABSTRACT

A voltage-nonlinear resistor has a sintered body of a composition comprising as a main constituent, zinc oxide (ZnO) and, as an additive, 0.1 to 3.0 mole percent of bismuth oxide (Bi2O3), 0.05 to 3.0 mole percent of antimony oxide (Sb2O3) and 0.1 to 3.0 mole percent of cobalt fluoride (CoF2). Electrodes are applied to opposite surfaces of the sintered body.

United States Patent [1 1 Matsuoka et al.

[4 1 Apr. 16, 1974 VOLTAGE-NONLINEAR RESISTORS Inventors: Mlchio Matsuoka, Yoshikazu Kobayashi; Hiroshi Oda; Takeshi Masuyama, all of Osaka, Japan Assignee: Matsushita Electric Industrial Co.,

Ltd., Kadoma, Osaka, Japan Filed: Feb. 23, 1973 Appl. No.: 335,423

Foreign Application Priority Data Mar. 1, 1972 Japan 47-21814 Mar. 1, 1972 Japan 47-21815 Mar. 1, 1972 Japan 47-2l816 Mar. 1, 1972 Japan 47-21817 Mar. 1, 1972 Japan.... 47-21818 Mar. 1, 1972 Japan.... 47-21819 Mar. 1, 1972 Japan 47-21820 US. Cl 317/61, 252/518, 338/21 Int. Cl. H02h 3/22 Field of Search 317/61, 61.5; 338/20, 21,

References Cited UNITED STATES PATENTS 6/1970 Stetson 317/61 2/1972 Masuyama et al.... 252/519 5/1972 Masuyama et al.... 252/519 X 9/1972 Anderson 317/61 X Primary Examiner-Roy N. Envall, Jr. Attorney, Agent, or Firm-Wenderoth, Lind & Ponack ABSTRACT A voltage-nonlinear resistor has a sintered body of a composition comprising as a main constituent, zinc oxide (ZnO) and, as an additive, 0.1 to 3.0 mole percent of bismuth oxide (B1203), 0.05 to 3.0 mole percent of antimony oxide (Sb O and 0.1 to 3.0 mole percent of cobalt fluoride (CoF Electrodes are applied to opposite surfaces of the sintered body.

6 Claims, 3 Drawing Figures PATENTEDAPR 16 I974 FIG. 3

FIG. 2

VOLTAGE-NONLINEAR RESISTORS The invention relates to voltage-nonlinear resistors having nonohmic resistance due to the bulk thereof and more particularly to varistors, which are available for characteristic elements of lightning arresters, comprising zinc oxide, bismuth oxide, antimony oxide and cobalt fluoride.

Various voltage-nonlinear resistors such as silicon carbide varistors, selenium rectifiers and germanium or silicon p-n junction diodes have been widely used for stabilization of voltage of electrical circuits or suppression of abnormally high surge induced in electrical circuits. The electrical characteristics of such a nonlinear resistor are expressed by the relation:

I=(V/C)" where V is the voltage across the resistor, I is the current flowing through the resistor, C is a constant corresponding to the voltage at a given current and exponent n is a numerical value greater than 1. The value of n is calculated by the following equation:

n glo (l2/ 1)/ g1o a/ 1) where V and V -are the voltages at given currents I and 1 respectively. The desired value of C depends upon the kind of application to which the resistor is to be put. It is ordinarily desirable that the value of n be as large as possible since this exponent determines the extent to which the resistors depart from ohmic characteristics. Conveniently, n-value defined by I,, I V, and V as shown in equation (2) is expressed by n for distinguishing from the n-value calculated by other currents or voltages.

Nonlinear: resistors comprising sintered bodies of zinc oxide with or without additives and non-ohmic electrode applied thereto, have already been disclosed as seen in U; S. Pat. Nos. 3,496,512, 3,570,002 and 3,503,029. The nonlinearity of such varistors is attributed to the interface between the sintered body of zinc oxide with or without additives and the silver paint electrode and is controlled mainly by changing the compositions of said sintered body and silver paint electrode. Therefore, it is not easy to control the C- value over a wide range after the sintered body is prepared. Similarly, in varistors comprising germanium or silicon p-n junction diodes, it is difficult to control the C-value over a wide range because the nonlinearity of these varistors is not attributed to the bulk but to the p-n junction. In addition, it is almost impossible for the varistors and germanium or silicon diode varistors to obtain the combination of C-value higher than 100 volt, n-value higher than and high surge resistance tolerable for surge more than IOOAp.

On the other hand, the silicon carbide varistors have nonlinearity due to the contacts among the individual grains of silicon carbide bonded together by a ceramic binding material, i.e., to the bulk, and the C-value is controlled by changing a dimension in the direction in which the current flows through the varistors. In addition, the silicon carbide varistors have high surge resistance which is available as characteristic elements of lightning arresters. The characteristic elements are used usually by connecting in series with discharging gaps and determine the level of the discharging voltage and the follow current. The silicon carbide varistors, however, have a relatively low n-value ranging from three to seven which results in poor suppression of lightning surge or increase in the follow current. Another defect of the arrester including the discharging gaps as its components is not to respond instantaneously surge voltage having very short rise time such as below lus. It is desirable for the arrester to suppress the lightning surge and the follow current to the level as low as possible and respond surge voltage instantaneously.

There have been known, on the other hand, voltagenonlinear resistors of bulk type comprising a sintered body of zinc oxide with additives comprising bismuth oxide and antimony oxide and/or cobalt oxide, as seen in U. S. Pat. No. 3,663,458. These zinc oxide varistors of bulk type are controllable in a C-value by changing the distance between electrodes and have an excellent nonlinear property in an n-value more than 10 in a region of current below than l0A/cm For a current more than l0A/cm however, the n-value goes down to a value below than 10. The power dissipation for surge energy shows a relatively low value compared with that of the conventional silicon carbide arrester, so that the change rate of C-value exceeds 20 percent after two standard lightning surges of 4 l0p.s wave form in a peak current of 1,500A/cm are applied to said zinc oxide varistor of bulk type. There is known another zinc oxide varistor of bulk type which contains as an additive cobalt fluoride as seen in U. S. Pat. No. 3,642,664. This varistor shows an excellent nonlinear property, but an essentially weak point as an arrester element is its weakness for surge pulse. The nonlinear property of the varistor deteriorates easily even for l00Ap/cm of surge pulse.

An object of the present invention is to provide a voltage-nonlinear resistor having nonlinearity due to the bulk thereof and being characterized by a high nvalue even in a range of current more than l0A/cm Another object of the present invention is to provide a voltage-nonlinear resistor having high power dissipation for surge energy.

Another object of the present invention is to provide 7 an arrester characterized by high suppression for lightning surge and low follow current.

These and other objects of the invention will become apparent upon consideration of the following description taken together with the accompanying drawing in which FIG. 1 is a partly cross-sectional view through a voltage-nonlinear resistor in accordance with the invention and FIG. 2 and FIG. 3 partly cross-sectional views through an arrester in accordance with the invention.

Before proceeding with a detailed description of the voltage-nonlinear resistors contemplated by the invention, their construction will be described with reference to FIG. 1 wherein reference character 10 designates, as a whole, a voltage-nonlinear resistor comprising, as its active element, a sintered body having a pair of electrodes 2 and 3 applied to opposite surfaces thereof. Said sintered body 1 is prepared in a manner hereinafter set forth. Wire leads 5 and 6 are attached conductively to the electrodes 2 and 3, respectively, by a connection means 4 as solder or the like.

lightning surge. Mr 7 A voltage-nonlinear resistor according to the invention comprises a sintered body of a composition comprising, as an additive, 0.1 to 3.0 mole percent of bismuth oxide (Bi O 0.05 to 3.0 mole percent of antimony oxide (Sb O and 0.1 to 3.0 mole percent of cobalt fluoride (CoF and the remainder of zinc oxide (ZnO) as a main constituent, and electrodes applied to opposite surfaces of said sintered body. Such a voltagenonlinear resistor has non-ohmic resistance due to the bulk itself. Therefore, its C-value can be changed without impairing the n-value by changing the distance between said opposite surfaces. According to the invention, said resistor has high n-value in a region of current -m r the," IRA swish?-heheeki i y f r are: 29. 35

The higher n-value in a region of current more than l0A/cm can be obtained when said sintered body further includes one member selected from the group consisting of 0.1 to 3.0 mole percent of cobalt oxide (C00) and 0.1 to 3.0 mole percent of manganese oxide According to the present invention, the higher n-' cent of cobalt fluoride (CoF 0.1 to 3.0 mole percent of cobalt oxide (C00), 0.] to 3.0 mole percent of manganese oxide (MnO) and one member selected from the group consisting of 0.05 to 3.0 mole percent of chromium oxide (Cr O 0.1 to 3.0 mole percent of tin oxide (SnO and 0.1 to 10.0 mole percent of silicon According to the present invention, the resistor is remarkably improved in the n-value in a regin of current more than A/cm and the stability for surge pulse when said sintered body consists essentially of 99.4 to 72 mole percent of zinc oxide (ZnO) and, as an additive, 0.1 to 3.0 mole percent of bismuth oxide (Bi O 0.05 to 3.0 mole percent of antimony oxide (Sb O 0.1 to 3.0 mole percent of cobalt fluoride (CoF 0.1 to 3.0 mole percent of cobalt oxide (C00), 0.1 to 3.0 mole percent of manganese oxide (MnO), 0.05 to 3.0 mole percent of chromium oxide (Cr O and 0.1 to 10.0 mole percent of silicon dioxide (SiO According to the present invention, when at least one voltage-nonlinear resistor consisting essentially of a sintered body of a composition comprising as a main constituent, zinc oxide and, as an additive, 0.1 to 3.0 mole percent of bismuth oxide (Bi O 0.05 to 3.0 mole percent of antimony oxide (Sb O and 0.1 to 3.0 'mole percent of cobalt fluoride (CoF and electrodes applied to opposite surfaces of said sintered body is applied to an arrester as a characteristic element, the resultant arrester is lowered in the follow current and improved in the suppression and power dissipation for According to the present invention, when at least one voltage-nonlinear resistor consisting essentially of a sintered body of 99.4 to 72.0 mole percent of zinc oxide (ZnO), 0.1 to 3.0 mole percent of bismuth oxide (Sb O 0.1 to 3.0 mole percent of cobalt fluoride Y (C01 0.1 to 3.0 mole percent of cobalt oxide (C00), 0.1 to 3.0 mole percent of manganese oxide (MnO), 0.05 to 3.0 mole percent of chromium oxide (Cr O and 0.1 to 10.0 mole percent of silicon dioxide (SiO and electrodes applied to opposite surfaces of said sintered body is applied as a characteristic element to an arrester, the resultant arrester is further lowered in the follow current and is further improved in the suppresaitr v rfi gat niqxl W 15sur e...

The sintered body 1 can be prepared by a per se well known ceramic technique. The starting materials in the compositions in the foregoing description are mixed in a wet mill so as to produce homogeneous mixtures. The mixtures are dried and pressed in a mold into desired shapes at a pressure from l(g./cm to 500 Kg./cm The pressed bodies are sintered in air at 1,000 to 1,450 C for 1 to 10 hours, and then furnace-cooled to room temperature (about 15 C to about 30 C). The mixtures can be preliminarily calcined at 700 to l,000 C and pulverized for easy fabrication in the subsequent pressing step. The mixture to be pressed can be admixed with a suitable binder such as water, polyvinyl alcohol, etc. It is advantageous that the sintered body be lapped at the opposite surfaces by abrasive powder such as silicon carbide in a particle size of 50p. in mean diameter to 10p. in mean diameter. The sintered bodies are provided, at the opposite surfaces thereof with electrodes in any available and suitable method such as silver painting, vacuum evaporation or flame spraying of r et l such as Al, Zn, Snetc V V.

The voltage-nonlinear properties are not practically affected by the kinds of electrodes used, but are affected by the thickness of the sintered bodies. Particularly, the C-value varies in proportion to the thickness of the sintered bodies, while the n-value is almost independent of the thickness. This surely means that the voltage-nonlinear property is due to the bulk itself, but not to the electrodes, i

Lead wires can be attached to the electrodes in a per se conventional manner by using conventional solder. It is convenient to employ a conductive adhesive comprising silver powder and resin in an organic solvent in order to connect the lead wires to the electrodes. Voltage-nonlinear resistors according to this invention have mgr stafiimyfiern paaim and fo r tlie surge test, which is carried out by applying lightning surge determined by the J EC (Japanese Electrotechnical Committee)-l56 Standard. The n-value and C-value do not change remarkably after heating cycles and surge test. It is advantageous for achievement of a high stability to humidity and high surge that the resultant voltagenonlinear resistors are embedded in a humidity proof resin such as epoxy resin and phenol resin in a per se When voltage-nonlinear resistors according to this invention are used as characteristic element, the resultant arrester is improved remarkably in the follow current and the suppression property for lightning surge. FIG. 2 is the cross-sectional view of an arrester wherein reference character 20 designates, as a whole, an ars? sszmrrisinaens was a emen insauesis:

element are connected inseries with one or more discharging gaps 12, spring 13 and line terminals 14 and 15. Said arrester elements are enveloped into wet- ,process porcelain 16. Said arrester is kept to the level age-nonlinear property of the sintered body is attributed to the sintered body inself.

TABLE 1 below than luA m the follow current and to the level higher than 2,000A/cm in the surge dissipation. FIG. 3 is the cross-sectional view of another arrester wherein reference character 30 designates, as a whole, an ar- 'r C n Sinuring rester comprising at least one voltage-nonlinear resistor 10". (m

inltlul 20) 1900 is 120m, 5m according to this invention. In the embodiment shown 1325 '5 20M. 5} FIG. 3, reference characters identical to those of FIG. 10 950 is l20()"(.. 5m 5 472 is [200%, SHr 2 have been employed to designate like elements. The initial (20) 750 5 350%.. Hr arrester of FIG. 3 18 characterized, in its construction, 1320 15 1 mg, m to be without discharging gap and, in its electrical prop- 15 :2 is erty, to have response time shorter than 0.1;zs for high initial 2500 6 1, surge having very sharp rise in addition to its excellent I5 1880 17 1000: C, 10Hr properties in follow current and surge dissipation. Presg 38 ently preferred illustrative embodiments of the invention are as follows. 20

M Example 2 x p 1 v Ir: Zinc oxide incorporated with bismuth oxide, antimony oxide, and cobalt fluoride in a composition of Table 2 is fabricated into the voltage-nonlinear resis- Starting material composed of 98.0 mole percent of tors by the same process as that of Example 1. The zmc mode, 0.5 mole percent of bismuth oxide, 1.0 mole thickness is 20 mm. The resulting electrical properties percent of antimony oxide, and 0.5 mole percent of 00- are shown in Table 2, in whichthe values of n, and n TABLE 2 Electrical properties of Additives (mol. resultant resistor Change rates after test 1 c (at n 0.1- n 100- B1203 Sb O cor2 1 mA) 1 mA) 1000 A) AC An, An

01 0.05 0.1 1450 13 10 I8 17 7.8 .1 .05 3.0 1100 13 11 I8 17 7.1 .1 3.0 .1 1980 12 12 17 19 6.9 .l 3.0 3.0 1700 13 ll 16 -16 8.1 3.0 .05 .1 2250 l4 l2 l6 l7 6.5 3.0 .05 3.0 2000 13 13 -l7 -l4 7.2 3.0 3.0 .1 2460 13 12 l5 15 6.1 3.0 3.0 3.0 2200 14 12 -15 -16 6.1 .5 1.0 .5 1900 16 14 l3 l3 -3.9

balt fluoride is mixed in a wet mill for 24 hours. The are the n-values defined between 0.1mA and lmA, and mixture is dried and pressed in a mold into discsof' between 100 and 1,000A, respectively. The impulse 40mm in diameter and 25mm in thickness at a pressure test is carried out by applying two impulses of 4 10p.s, t999il eaabsea i y unssrstqq lbw om ne addition of bisr'nuth oxide, antimony oxide, and cobalt The pressed bodies are sintered in air at the condition shown in Table 1, and then furnace-cooled to room temperature. The sintered body is lapped at the opposite surfaces thereof into the thickness shown in Table 1 by silicon carbide abrasive in particle size of 30p. in mean diameter. The opposite surfaces of the sintered body are provided with a spray metallized film of alu- 'Pinum in eusstsez sllkn n @bl ia -h change rates.

fluoride as additives show the high n-value and small Example 3 of C and n values after impulse test carried out by same method as that of Example 2 are also shown in Table .3. It will be readily realized that the further addition of cobalt oxide or manganese oxide results in the higher n-value and smaller change rates than those of Example TABLE 3 Electrical properties of Additives (mol. resultant resistor Change rates after test C (at n (0.1- n, (100- B1 03 Sbz COP: C00 MnO 1 mA) 1 mA) 1000 A) AC An, An

0.1 0.05 0.1 0.1 1100 15 12 14 14 7.0 .1 .05 .1 3.0 1140 15 12 -13 -14 6.7 .1 .05 3.0 .1 920 16 13 -13 -12 6.1 .1 3.0 .1 .1 1400 17 13v -14 -11 -6.3 3.0 .05 .1 .1 1190 17 13 -13 -14 -6.9 .1 .05 3.0 3.0 1200 18 12 12 12 -7.1 .1 3.0 .1 3.0 1410 17 11 12 -13 5.9 3.0 .05 .1 3.0 1350 17 13 '11 -14 -5.7 .1 3.0 3.0 .l 1310 18 11 13 12 6.2 3.0 .05 3.0 .1 1280 17 14 -14 -13 4.8 3.0 3.0 .1 .1 1640 18 12 -13 -14 -5.7 .l 3.0 3.0 3.0 1610 18 14 -14 -11 5.3 3.0 .05 3.0 3.0 1550 17 13 -12 -13 -6.0 3.0 3.0 .1 3.0 1950 l7 l4 .12 12 5.9 3.0 3.0 3.0 .1 1720 18 15 -11 -12 -6.0 3.0 3.0 3.0 3.0 1900 19 14 -13 4.4 .5 1.0 .5 .5 1600 20 16 -10 -8.5 -3.0 .1 .05 .1 1200 16 12 -13 -13 -7.1 .1 .05 .1 1200 16 13 12 -14 -7.3 .1 .05 v 3.0 1050 15 12 -14 -13 6.2 .1 3.0 .1 1450 17 12 -14 -12 6.6 3.0 .05 .1 1230 16 13 12 -14 -7.0 .1 .05 3.0 1250 18 14 -12 -13 -5.9 .1 3.0 .1 1480 19 16 -12 -11 -5.7 3.0 .05 .1 1400 13 -14 -11 6.0 .1 3.0 3.0 1390 17 12 -11 10 4.8 3.0 .05 3.0 1340 17 15 -13 -10 -5.0 3.0 3.0 1.0 1700 16 15 12 -10 -4.9 .1 3.0 3.0 1680 18 17 -10 -9.9 -5.5 3.0 .05 3.0 1620 19 14 12 -11 -5.3 3.0 3.0 .1 2050 18 16 -11 -9.5 -4.8 3.0 3.0 3.0 1800 20 16 -12 -10 4.2 3.0 3.0 3.0 2000 21 15 -13 -9.0 -5.1 .5 1.0 .5 1900 23 18 -10 -8.3 3.2

Example 4 Zinc oxide and additives of Table 4 is fabricated into the voltage-nonlinear resistors by the same process as Example 1. The electrical characteristics of resulting resistors are sho rr in Table 4. It will beeasilyynder IQ QIHQLIEQIPUP ait nszf ti xidasm m um oxide, silicon dioxide or chromium oxide and silicon dioxide results in the higher n-value and smaller change rates than those of Example 3. The change rates of C and n values after impulse test carried out by same I method as that of Example 2 are also shown in Table -4.

TABLE 4 Electrical properties of Additives (mol. resultant resistor Change rates after test C (at m (0.1- n; (100- B1303 S1320: CoF, C00 MnO SnO, CF20: S10: 1 mA) 1 mA) 1000 A) AC Am An Additives (mol.

Electrical properties of resultant resistor Change rates after test cm m (0.1- n. (100- BuO Sb|O CoF, C MnO SnO| CriO S10, 1 mA) 1 mA) 1000 A) AC An. Am

-- 3.0 3.0 3.0 3.0 .1 3510 39 20" ':io T .7 W 3.0 3.0 3.0 3.0 .5 4060 44 19 8.4 7.2 -4.9 3.0 3.0 3.0 3.0 10.0 7800 38 19 9.5 8.4 5.3

.l .05 .l .l .5 3100 48 22 7.8 --6.8 2.6

Example carried out by the same method as that of Example 6.

The resistors of Example 2, 3 and 4 are tested in ac- 2O cordance with a method widely used in the electronic components parts. The heating cycle test is carried out by repeating five times the cycle in which said resistors are kept at 85 C ambient temperature for 30 minutes,

cooled rapidly to C and then kept at such temper- 25 ature for minutes. The humidity test is carried out at C and 95 percent relative humidity for 1,000 hrs. Table 5 shows the average change rates of C-value and n-value of resistors after heating cycle test and humidity test. It is easily understood that each sample has a 3 js mall change rate TABLE 5 1 The voltage-nonlinear resistors according to Example 2, 3 and 4 are constructed to the arrester as shown in FIG. 2 by series connection of three pieces of resistor and one discharging gap. The C-value of said total pieces of voltage-nonlinear resistor is about 7,000V. The impulse test are carried out by applying two impulses of 4 l0p.s, 1,500A/cm superposed on AC 3,000V. The follow current of the arrester shows the value lower than 1 1 A as shown in Table fi arrd t he A change rates of electrical properties after test show same results as the impulse test of Example 2, 3 and 4.

TABLE 6 Sample No. Follow-current Example 2 below than lpA Example 3 below than 0.5 .A Example 4 below than 0.1,.LA

Example 7 The voltage-nonlinear resistors according to Example 2, 3 and 4 are constructed to the arrester as shown in FIG. 3 by series connection of three pieces of resis tor. The value of C of said total pieces of voltagenonlinear resistor is about 7,000V. The impulse test are The follow current shows the value lower than lpAas shown in Table 0 and the change rates of electrical properties after test show same results as that of the impulse test in Example 2, 3 and 4. Another impulse test are carried out by applying impulse having the value of 0.0lp.s in rise time. The rise time of current flowing through said arrester is lower than 0.05p.s.

What is claimed is:

1. A voltage-nonlinear resistor consisting essentially of a sintered body of a composition comprising as a main constitutent, zinc oxide (ZnO) and, as an additive, 0.1 to 3.0 mole percent of bismuth oxide (Bi O 0.05 to 3.0 mole percent of antimony oxide (Sb O and 0.1 to 3.0 mole percent of cobalt fluoride (C01 and electrodes applied to opposite surfaces of said sintered body? 2. A voltage-nonlinear resistor defined by claim 1, wherein said sintered body further includes one member selected from the group consisting of 0.1 to 3.0 mole percent of cobalt oxide (C00) and 0.1 to 3.0 mole percent of manganese oxide (MnO).

3. A voltagenonlinear resistor defined by claim 1, wherein said sintered body further includes 0.1 to 3.0 mole percent of cobalt oxide (CoO), 0.1 to 3.0 mole percent of manganese oxide (MnO) and one member selected from the group consisting of 0.05 to 3.0 mole percent of chromium oxide (Cr O 0.1 to 3.0 mole percent of tin oxide (SnO and 0.1 to 10.0 mole percent of silicon dioxide (SiO 4. A voltage-nonlinear resistor defined by claim 1, wherein said sintered body consists essentially of 99.4 to 72.0 mole percent of zinc oxide (ZnO) 0.1 to 3.0 mole percent of bismuth oxide (Bi O 0.05 to 3.0 mole percent of antimony oxide (Sb O 0.1 to 3.0 mole percent of cobalt fluoride (C01 0.1 to 3.0 mole percent of cobalt oxide (C00), 0.1 to 3.0 mole percent of manganese oxide (MnO), 0.05 to 3.0 mole percent of chromium oxide (Cr O and 0.1 to 10.0 mole percent of silicon dioxide (SiO 5. An arrester comprising at least one voltagenonlinear resistor of claim 1 as a characteristic element.

6. An arrester comprising at least one voltagenonlinear resistor of claim 4 as a characteristic element. 

2. A voltage-nonlinear resistor defined by claim 1, wherein said sintered body further iNcludes one member selected from the group consisting of 0.1 to 3.0 mole percent of cobalt oxide (CoO) and 0.1 to 3.0 mole percent of manganese oxide (MnO).
 3. A voltage-nonlinear resistor defined by claim 1, wherein said sintered body further includes 0.1 to 3.0 mole percent of cobalt oxide (CoO), 0.1 to 3.0 mole percent of manganese oxide (MnO) and one member selected from the group consisting of 0.05 to 3.0 mole percent of chromium oxide (Cr2O3), 0.1 to 3.0 mole percent of tin oxide (SnO2) and 0.1 to 10.0 mole percent of silicon dioxide (SiO2).
 4. A voltage-nonlinear resistor defined by claim 1, wherein said sintered body consists essentially of 99.4 to 72.0 mole percent of zinc oxide (ZnO) 0.1 to 3.0 mole percent of bismuth oxide (Bi2O3), 0.05 to 3.0 mole percent of antimony oxide (Sb2O3), 0.1 to 3.0 mole percent of cobalt fluoride (CoF2), 0.1 to 3.0 mole percent of cobalt oxide (CoO), 0.1 to 3.0 mole percent of manganese oxide (MnO), 0.05 to 3.0 mole percent of chromium oxide (Cr2O3) and 0.1 to 10.0 mole percent of silicon dioxide (SiO2).
 5. An arrester comprising at least one voltage-nonlinear resistor of claim 1 as a characteristic element.
 6. An arrester comprising at least one voltage-nonlinear resistor of claim 4 as a characteristic element. 